The Division of Intramural Population Health Research (DIPHR) conducts studies focusing on child health and human development. As part of DIPHR's mission, one area of interest is the investigation of the developmental origins of health disparities - i. e., differences in developmental outcomes between socially advantaged and disadvantaged groups. Thus, disparities typically refer to unequal health outcomes between socioeconomic and race/ethnic groups and may also exist in the context of other socially disadvantaged statuses including intellectual disability and sexual minority status. Health disparities in the United States - in life expectancy and chronic disease - have their origins as early as the prenatal period. Early life conditions including poverty and discrimination generate disparities in health over the life course that become further entrenched in the population through their transmission across generations. Parental mental health, which is strongly linked with social and economic disadvantage as well as child development, may play a key mediating role in the transmission of disparities across generations, but a persistent gap in the disparity's literature is that both maternal and paternal psychopathology has not been fully considered as mechanisms contributing to disparities nor have they been measured using phenotypically validated approaches. As a result, though disparities in health are well documented, the developmental mechanisms that impact disparities at the very beginning of life are not, particularly those which lead to developmental deficits that emerge long before disease states. The NTH strategic plan (2016-2020) highlights the need for research to improve understanding mechanisms that lead to disparities by race/ethnicity and socioeconomic status. Such enhanced understanding is needed to clarify the etiology of disparities - pa1ticularly the specific exposures linked with social or economic disadvantage that impact early development. Advancing knowledge of the developmental mechanisms that generate disparities requires a more thorough understanding of how socioeconomic status and race/ethnicity, along with other statuses associated with disparities such as disability status and sexual minority status, influence the determinants of development from gestation onward. To accomplish this, more in-depth measurement of potential causes of disparities is needed from more diverse samples starting earlier in the life course than is currently available from existing studies . This work needs to take a developmental systems perspective in which multiple domains of child development are influenced by inputs at the family, neighborhood, and community levels , and in which small differences early in child development are compounded over time resulting in large gaps in health later on.